Tufted textile articles are made by inserting a plurality of vertical, reciprocating needles threaded with yarn into a moving primary backing fabric to form tufts of yarn. Loopers or hooks, which work in a timed relationship with the stroke of the needles, are located below the primary backing so that the loopers are positioned just above the needle eye when the needles are at the lowest point in their downward stroke. When the needles reach the lowest point in the downward stroke, the yarn is picked up from the needles by the loopers and held momentarily. Loops or tufts of yarn are formed as the needles are drawn back through the backing fabric. This process is repeated when the previously formed loops are moved away from the loopers as the backing fabric is advanced.
The loops can be cut during the tufting process to form a cut pile as opposed to a loop pile construction. If a cut pile is desired, a looper and knife combination is used in the tufting process.
Additional information on the manufacture of tufted articles may be found in Rose, Stanley H., "Tufted Materials", Man-Made Textile Encyclopedia, Chap IX, Textile Book Publishers, Inc., (1959).
When the tufted article is a carpet, the primary backing fabric is typically a woven or nonwoven fabric made of one or more of natural and synthetic fibers, such as jute, wool, rayon, polyamides, polyesters, polypropylene and polyethylene, or of films of synthetic materials, such as polypropylene, polyethylene, and copolymers thereof.
The tufts of yarn inserted during the tufting process are usually held in place by the untwisting action of the yarn in combination with the shrinkage of the backing fabric. However, when the article is a tufted carpet, the back of the backing fabric may be coated with a backcoat material, such as a latex or emulsion of natural or synthetic rubbers or synthetic resins, or a hot melt adhesive, to assist in locking or anchoring the tufts to the backing material, to improve the dimensional stability of the tufted carpet, to make the carpet more durable and to provide skid and slip resistance.
Generally, the tufted carpet is further stabilized by laminating a secondary backing, such as jute, woven or nonwoven fabrics made from polypropylene, polyethylene, and copolymers thereof, to the tufted carpet. When the backcoating material is a hot melt adhesive, the adhesive helps bond the primary backing fabric to the secondary backing fabric.
Carpets bonded with a hot melt adhesive generally use a pre-coat composition comprising a resin, a wax, and optionally, a naphthenic oil, which is applied to the primary backing prior to backcoating the backing fabric with the hot melt adhesive. The precoat is applied in an amount sufficient to penetrate the individual tufts of yarn thereby increasing the resistance of the tufts to pull-out, known as tuft-bond strength or pile-bond strength, and enhancing the bonding of the primary backing fabric to the backcoating adhesive. The amount of precoat necessary to penetrate the individual tufts will vary depending on the carpet yarn density and the efficacy of the precoat.